KR20070121502A - Optical pickup device - Google Patents

Abstract

An optical pickup device is provided to record and reproduce information in three kinds of optical information recording media, and to reduce the number of parts by using three different types of semiconductor laser devices and sharing each device regardless of the type of laser beams. An optical pickup device comprises first to third semiconductor laser devices(104,113,114), a collimating lens(103), a beam splitter(102), first to third hologram devices(108,109,110), and a plurality of light receiving device groups(115,116,117). The first to third semiconductor laser devices emit first to third laser beams respectively. The beam splitter focuses the laser beams on the collimating lens. The first to third hologram devices diffract the first to third laser beams passing through the beam splitter into ± first diffraction beams. The light receiving device groups receive the first diffraction beams. The second semiconductor laser device, the third semiconductor laser device, and the light receiving device groups are in the same light source/detection unit.

Description

Optical pickup device {OPTICAL PICKUP DEVICE}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing the construction of an optical pickup apparatus according to a first embodiment of the present invention.

Fig. 2 is a sectional view showing the optical path of the first outgoing light in the optical pickup apparatus according to the first embodiment.

Fig. 3 is a sectional view showing an optical path of the second output light in the optical pickup apparatus according to the first embodiment.

Fig. 4 is a sectional view showing an optical path of the third output light in the optical pickup apparatus according to the first embodiment.

Fig. 5 is a top view showing the configuration of a first polarization hologram element in the optical pickup apparatus according to the first embodiment.

Fig. 6 is a top view showing the structure of a second polarization hologram element in the optical pickup device of the first embodiment.

Fig. 7 is a top view showing the configuration of a third polarization hologram element in the optical pickup apparatus according to the first embodiment.

Fig. 8 is a top view showing the arrangement of light receiving element groups in the optical pickup apparatus according to the first embodiment.

Fig. 9 is a top view showing the diffraction spot of the first emitted light in the optical pickup apparatus of the first embodiment.

Fig. 10 is a top view showing the diffraction spot of the second emitted light in the optical pickup apparatus according to the first embodiment.

Fig. 11 is a top view showing the diffraction spot of the third emitted light in the optical pickup apparatus of the first embodiment.

Fig. 12 is a sectional view showing the construction of an optical pickup apparatus relating to a second embodiment of the present invention.

Fig. 13 is a sectional view showing the optical path of the first outgoing light in the optical pickup apparatus relating to the second embodiment.

Fig. 14 is a sectional view showing the optical path of the second outgoing light in the optical pickup apparatus relating to the second embodiment.

Fig. 15 is a sectional view showing the optical path of the third output light in the optical pickup apparatus of the second embodiment.

Fig. 16 is a sectional view showing the construction of an optical pickup apparatus according to a third embodiment of the present invention.

Fig. 17 is a sectional view showing the construction of an optical pickup apparatus according to a fourth embodiment of the present invention.

Fig. 18 is a sectional view showing the construction of an optical pickup apparatus according to a fifth embodiment of the present invention.

19 is a top view showing the structure of a conventional optical pickup device.

Explanation of symbols on the main parts of the drawings

1, 3, 5, 107: light source / detection unit 2, 4, 6, 103: collimating lens

7, 9, 102: beam splitter 8: aberration correction element

10 polarized mirror 11 objective lens

12: conventional optical pickup device 101, 201, 301, 401, 501: optical pickup device

104: first semiconductor laser device 105: first diffraction grating

106: quarter wave plate 108: first polarization hologram element

109: second polarization hologram element 110: third polarization hologram element

111: second diffraction grating 112: integrated substrate

113: second semiconductor laser device 114: third semiconductor laser device

115: first light receiving element group

115a, 115b, 115c, 115d: first light receiving element region

116: second light receiving element group

116a, 116b, 116c, and 116d: second light receiving element region

117: third light receiving element group

117a, 117b, 117c, and 117d: third light receiving element area

118: first exit light 119: second exit light

120: third outgoing light 121: first area

121a and 121b: first rectangular area 122: second area

122a, 122b: second rectangular area 123: third area

123a, 123b: third rectangular area 124: fourth area

124a, 124b: fourth rectangular area 125: fifth area

125a, 125b: fifth rectangular area 126: sixth area

126a and 126b: sixth rectangular area 127: seventh area

127a and 127b seventh rectangular area 128 eighth area

128a, 128b: 8th rectangular area 129: 9th area

129a and 129b: 9th rectangular area 130: 10th area

130a and 130b: tenth rectangular area 131: eleventh area

131a and 131b: Eleventh rectangular area 132: Twelfth area

132a, 132b: 12th rectangular area

L1: light emitting point of the second semiconductor laser element

L2: Light emitting point of the third semiconductor laser device

L101a, L101b, L101c, L101d, L101e, L101f,

L102a, L102b, L102c, L102d, L102e, L102f,

L103a, L103b, L103c, L103d, L103e, L103f,

L104a, L104b, L104c, L104d, L104e, L104f: diffraction spot in the first emitted light

L201a, L201b, L201c, L201d, L201e, L201f,

L202a, L202b, L202c, L202d, L202e, L202f,

L203a, L203b, L203c, L203d, L203e, L203f,

L204a, L204b, L204c, L204d, L204e, L204f: diffraction spot in the second emitted light

L301a, L301b, L301c, L301d, L301e, L301f,

L302a, L302b, L302c, L302d, L302e, L302f,

L303a, L303b, L303c, L303d, L303e, L303f,

L304a, L304b, L304c, L304d, L304e, L304f: diffraction spot in the third emitted light

313: fourth semiconductor laser device

418: fourth polarization hologram element

511: transparent member

518: fifth polarization hologram element

The present invention relates to an optical pickup apparatus for recording or reproducing information on an optical information recording medium.

Recently, various optical information recording media such as CD, DVD, Blu-ray Disc, HD DVD, etc. have been formulated and put into practical use, and various recording media can be recorded or reproduced regardless of the specifications of various optical information recording media. The demand for such a device can be increased (see Japanese Patent Application Laid-Open No. 2004-103135).

19 is a top view showing the structure of a conventional optical pickup apparatus. As shown in Fig. 19, the conventional optical pickup apparatus 12 includes light source / detecting units 1, 3, and 5, collimating lenses 2, 4 and 6, beam splitters 7 and 9, and aberration correction. An element 8, a polarizing mirror 10, and an objective lens 11 are provided. The light source / detecting unit 1 and the collimating lens 2 are for short wavelengths and are used for Blu-ray Disc or HD DVD Disc. In addition, the light source / detecting unit 3 and the collimating lens 4 are for medium wavelength and used for DVD. The light source / detecting unit 5 and the collimating lens 6 are for long wavelengths and used for CD.

However, in the conventional optical pickup device 12, since the light source / detecting unit and the collimating lens are configured for each wavelength, the number of parts increases. For this reason, the cost rises and high assembly precision is required.

For such a problem, for example, an optical pickup device constituted by two by reducing the number of light sources / detection units has been proposed (see Japanese Patent Application Laid-Open No. 2001-184705). In this configuration, however, the hologram elements are separately configured so that two light receiving elements are used. For this reason, sufficient cost reduction cannot be achieved and high assembly precision is also required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical pickup apparatus capable of recording or reproducing information on various optical information recording media, reducing the number of parts, miniaturizing, and easily assembling. It is done.

In order to achieve the above object, the optical pickup device of the present invention comprises a first semiconductor laser device that emits a first light beam, a second semiconductor laser device that emits a second light beam, and a third semiconductor laser that emits a third light beam. A collimating lens for parallelizing an element, the first light beam, the second light beam and the third light beam, the first light beam, the second light beam, and the third light beam to reflect or transmit the collimating lens A beam splitter for condensing with a lens, a first hologram element for diffracting the first light beam reflected by the recording surface of the optical information recording medium and passing through the beam splitter with ± 1st order diffracted light, and the optical information recording medium A second hologram element which is reflected on the recording surface of the optical beam and passes through the beam splitter and diffracts the second light beam with ± 1st order diffracted light, and on the recording surface of the optical information recording medium, A third hologram element diffracting the third light beam passing through the device into ± 1st order diffracted light, and the ± 1st diffraction light diffracted by the first hologram element, the second hologram element, and the third hologram element And a plurality of light receiving element groups for receiving the light, wherein the second semiconductor laser element, the third semiconductor laser element, and the plurality of light receiving element groups are configured in the same light source / detection unit.

According to the above configuration, three semiconductor laser elements, the second semiconductor laser element, the third semiconductor laser element, and the plurality of light receiving element groups are arranged in the same light source / detection unit, so that the light source / detection unit is configured for each wavelength. The number of parts can be reduced as compared with the conventional optical pickup apparatus. In addition, since the collimating lens, the beam splitter, and the plurality of light receiving element groups are commonly used regardless of the type of the light beam, the number of parts can be further reduced. As a result, three kinds of optical information recording medium standards can be supported, and the optical pickup device can be realized in a small size and easy to assemble.

In addition, the optical pickup device of the present invention is disposed on the optical path of the first light beam from the first semiconductor laser element to the beam splitter, and a first diffraction grating for diffracting the first light beam into a main beam and a sub beam It is preferable to further provide.

In addition, the optical pickup device of the present invention is disposed on the optical path of the second light beam from the second semiconductor laser element to the beam splitter, and the third light beam from the third semiconductor laser element to the beam splitter, It is preferable to further include a second diffraction grating for diffracting the second light beam and the third light beam into a main beam and a sub beam. In this case, it is more preferable that the second diffraction grating is disposed on the light source / detection unit so as to be positioned above the second semiconductor laser element and the third semiconductor laser element. As a result, since the light source / detection unit and the second diffraction grating are integrated, the optical pickup device of the present invention can be easily assembled.

In the optical pickup device of the present invention, it is preferable that the first hologram element, the second hologram element, and the third hologram element are disposed between the beam splitter and the second diffraction grating. In this case, it is more preferable if the first hologram element, the second hologram element, and the third hologram element are integrally formed, and the first hologram element, the second hologram element, the third hologram element, and the second hologram element are integrally formed. It is particularly preferable if the diffraction grating is formed integrally with the light source / detecting unit.

Thereby, assembling precision of the optical pickup apparatus can be improved compared with the case where each member is comprised individually. As a result, it is possible to realize an optical pickup device that is compact and easy to assemble.

Further, in the optical pickup device of the present invention, the first light beam emitted by the first semiconductor laser element can be focused onto the optical information recording medium without passing through the polarization hologram element. As a result, the energy loss of the laser light caused by passing through the polarization hologram element can be suppressed, and an optical pickup device having good light efficiency can be realized.

The first light beam is preferably a light beam in the 405 nm band, the second light beam is a light beam in the 650 nm band, and the third light beam is a light beam in the 780 nm band. As a result, the optical pickup apparatus of the present invention can record and reproduce information on Blu-ray Discs, DVDs, and CDs.

Further, it is preferable that the main beam of the first light beam and the main beam of the second light beam substantially coincide with the optical axes of the collimating lens on the collimating lens, respectively. This allows the first light beam and the second light beam to enter the objective lens at an optimal position and angle, thereby improving the quality of the beam spot shape on the optical information recording medium. Therefore, the specification corresponding to the first light beam and the second light beam is reduced. It is possible to accurately record and reproduce information on each optical information recording medium. As a result, a high-performance optical pickup device corresponding to the standard of each optical information recording medium can be realized.

Here, when the second semiconductor laser element and the third semiconductor laser element are integrally formed as a monolithic two-wavelength semiconductor laser element, the number of parts can be further reduced, which is preferable.

In the optical pickup device of the present invention, it is preferable that all of the first hologram element, the second hologram element, and the third hologram element are polarization hologram elements.

In addition, it is preferable that both the first hologram element and the second hologram element are polarization hologram elements, and the third hologram element is a non-polarization hologram element. Thus, even when the optical information recording medium corresponding to the wavelength of the third light beam is a coarse optical information recording medium, the optical pickup device can stably perform the writing operation.

The optical pickup device of the present invention preferably further comprises a quarter wave plate between the beam splitter and the collimating lens.

Here, it is preferable that the optical pickup device of the present invention further includes an operation unit for detecting an electrical signal outputted from the plurality of light receiving element groups and generating a focus error signal or a tracking error signal based on the detection result. Do.

The above and other objects and features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

EXAMPLE

[First Embodiment]

The configuration of the optical pickup apparatus according to the first embodiment of the present invention and the operation of the optical pickup apparatus will be described with reference to the drawings. Here, in the present specification, the main beam means zero-order diffracted light and the sub-beam means ± first-order diffracted light, respectively.

-Composition of optical pickup device

1 is a cross-sectional view showing the configuration of an optical pickup apparatus according to a first embodiment of the present invention. As shown in Fig. 1, the optical pickup apparatus of this embodiment includes three semiconductor laser elements to correspond to three types of optical information recording media. The first semiconductor laser device 104 emits a laser beam (light beam) in the 405 nm band conforming to the Blu-ray Disc standard. The second semiconductor laser device 113 emits 650 nm laser light (light beam) in compliance with the DVD standard, and the third semiconductor laser device 114 emits 780 nm laser light (light beam) in accordance with the CD standard. do. In this embodiment, the laser light emitted from the first semiconductor laser device 104 in the 405 nm band is referred to as the first output light 118 (see FIG. 2). Similarly, the 650 nm laser beam emitted from the second semiconductor laser element 113 is used as the second emission light 119 (see FIG. 3), and the 780 nm laser beam emitted from the third semiconductor laser element 114 is generated. It is assumed that 3 output light 120 (refer FIG. 4).

The optical pickup device 101 of the present embodiment includes a first semiconductor laser device 104, a first diffraction grating 105, a beam splitter 102, a quarter wave plate 106, and a collimating lens 103. , A first polarization hologram element 108 and a second polarization hologram element 109 sequentially arranged from the light splitter 102 side between the light source / detection unit 107, the light source / detection unit 107, and the beam separator 102. And a third polarization hologram element 110. The first diffraction grating 105 is disposed between the first semiconductor laser device 104 and the beam splitter 102. Further, the quarter wave plate 106 is disposed between the beam splitter 102 and the collimating lens 103.

The light source / detecting unit 107 includes an integrated substrate 112, a second semiconductor laser device 113, a third semiconductor laser device 114, a first light receiving device group 115, and a second light receiving device group 116. , A third light receiving element group 117, and a second diffraction grating 111. The second diffraction grating 111 is formed above the second semiconductor laser device 113 and the third semiconductor laser device 114 on the lower surface of the transparent member 511 made of a glass plate or the like.

 The first semiconductor laser device 104 is disposed such that the main beam of the first output light 118 is perpendicular to the optical axis of the collimating lens 103. The first output light 118 enters the beam splitter 102 via the first diffraction grating 105. In the beam splitter 102, the first output light 118 is reflected, and the reflected light is directed to the collimating lens 103.

Meanwhile, the second emission light 119 and the third emission light 120 pass through the beam splitter 102. The reflected light from the optical information recording medium passes through the beam separator 102 and is directed to the first polarization hologram element 108, the second polarization hologram element 109, and the third polarization hologram element 110.

The first polarization hologram element 108 is designed to diffract the first outgoing light 118 and to transmit the second outgoing light 119 and the third outgoing light 120. Similarly, the second polarization hologram element 109 diffracts only the second output light 119. In addition, the third polarization hologram element 110 diffracts only the third output light 120.

Operation of optical pickup device

The operation of the optical pickup apparatus 101 according to the present embodiment will be described with reference to Figs. In the optical pickup apparatus 101 of this embodiment, after the standard conforming to the optical information recording medium is determined, the laser light is irradiated onto the optical information recording medium using a semiconductor laser element corresponding to the conforming standard.

First, the case where the 1st semiconductor laser element 104 which emits the laser beam of 405nm band which conforms to Blu-ray Disc standard is used is demonstrated. 2 is a cross-sectional view showing the optical path of the first output light 118 in the optical pickup apparatus 101 of this embodiment.

As shown in FIG. 2, the first output light 118 is diffracted by the first diffraction grating 105 into a main beam and a sub beam. The diffracted first output light 118 is reflected by the beam splitter 102 and passes through the quarter wave plate 106 and parallelized by the collimating lens 103. Thereafter, the first output light 118 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The first output light 118 reflected on the recording surface passes through the beam separator 102 and enters the first polarization hologram element 108. The first output light 118 is diffracted by the first polarization hologram element 108 into ± first order diffracted light, and then passes through the second polarization hologram element 109 and the third polarization hologram element 110. Thereafter, the first output light 118 enters the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 117.

Next, the case where the 2nd semiconductor laser element 113 which emits the laser light of 650 nm band which conforms to DVD standard is used is demonstrated. 3 is a cross-sectional view showing the optical path of the second output light 119 in the optical pickup device 101 of the present embodiment.

As shown in FIG. 3, the second emitted light 119 is diffracted by the second diffraction grating 111 into a main beam and a sub beam. The diffracted second output light 119 passes through the beam splitter 102 and then passes through the quarter wave plate 106 and is parallelized by the collimating lens 103. Thereafter, the second output light 119 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The second outgoing light 119 reflected on the recording surface passes through the beam separator 102 through the same optical path as the outgoing path, and then passes through the first polarizing hologram element 108 and the second polarizing hologram element 109. Incident The second output light 119 is diffracted by the second polarization hologram element 109 into ± first order diffracted light, and then passes through the third polarization hologram element 110. Thereafter, the second emission light 119 enters the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 117.

In addition, the case where the third semiconductor laser element 114 that emits laser light in the 780 nm band in accordance with the CD standard is used will be described. 4 is a cross-sectional view showing the optical path of the third output light 120 in the optical pickup device 101 of the present embodiment.

As shown in FIG. 4, the third output light 120 is diffracted by the second diffraction grating 111 into the main beam and the sub beam similarly to the second output light 119. The diffracted third output light 120 passes through the beam splitter 102 and the quarter wave plate 106 in turn and is parallelized by the collimating lens 103. Thereafter, the third output light 120 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The third output light 120 reflected from the recording surface passes through the beam separator 102 through the same optical path as the exit path, and then passes through the first polarization hologram element 108 and the second polarization hologram element 109. And incident on the third polarization hologram element 110. The third output light 120 is diffracted by the first polarization hologram element 110 to ± 1st order diffracted light, and then the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 116, and a third light source. It enters into the light receiving element group 117.

As described above, the outgoing light of each semiconductor laser element is reflected by the recording surface of the optical information recording medium, and then diffracted by ± 1st order diffracted light in the polarization hologram element corresponding to each wavelength and enters into each light receiving element group. Here, the operation in which the outgoing light of each semiconductor laser element having the main beam and the sub beam is diffracted by the polarization hologram elements corresponding to the respective wavelengths and guided to the respective light receiving element groups will be described in more detail.

First, the case where the first output light 118 is diffracted by the first polarization hologram element 108 will be described. Fig. 5 is a top view showing the configuration of the first polarization hologram element 108 related to the optical pickup device of this embodiment.

As shown in FIG. 5, the first polarization hologram element 108 is divided into a first region 121, a second region 122, a third region 123, and a fourth region 124. Each divided area is subdivided into rectangular areas. In the first area 121, the first rectangular areas 121a and 121b are alternately arranged. Similarly, in the second region 122, the second rectangular regions 122a and 122b are used, in the third region 123, the third rectangular regions 123a and 123b are used, and in the fourth region 124, the fourth rectangular region ( 124a and 124b are alternately arranged, respectively. In addition, the center of the first polarization hologram element 108 substantially overlaps the optical axis of the collimating lens 103 in plan view.

The first outgoing light 118 reflected from the surface of the optical information recording medium is diffracted in the X-direction shown in FIG. 5 in the first region 121 of the first polarization hologram element 108, and thus the first-order diffracted light The first light receiving element group 115 and the third light receiving element group 117 are guided. Similarly, ± first-order diffracted light diffracted in the X direction in the second region 122 is guided to the first light receiving element group 115 and the third light receiving element group 117. Further, the ± first order diffracted light diffracted in the X direction in the third region 123 is led to the second light receiving element group 116 and the third light receiving element group 117. Further, the ± first order diffracted light diffracted in the X direction in the fourth region 124 is led to the second light receiving element group 116 and the third light receiving element group 117.

Next, the case where the second emission light 119 is diffracted by the second polarization hologram element 109 will be described. Fig. 6 is a top view showing the configuration of the second polarization hologram element 109 related to the optical pickup device of this embodiment.

As shown in FIG. 6, the second polarization hologram element 109 is similar to the first polarization hologram element 108 in the fifth region 125, the sixth region 126, the seventh region 127, and the fifth polarization hologram element 108. It is divided into four regions represented by eight regions 128. Each divided area is subdivided into rectangular areas, respectively. In the fifth region 125, the fifth rectangular regions 125a and 125b, the sixth region 126, the sixth rectangular regions 126a and 126b, and in the seventh region 127, the seventh rectangular regions 127a, 127b), in the eighth region 128, eighth rectangular regions 128a and 128b are alternately arranged. The center of the second polarization hologram element 109 substantially overlaps with the optical axis of the collimating lens 103 in plan view.

The second outgoing light 119 reflected from the surface of the optical information recording medium is diffracted in the X direction shown in FIG. 6 in the fifth region 125 of the second polarization hologram element 109 so that the ± first-order diffracted light Guided to the first light receiving element group 115 and the third light receiving element group 117. Similarly, the ± first order diffracted light diffracted in the X direction in the sixth region 126 is guided to the first light receiving element group 115 and the third light receiving element group 117. Further, the ± first order diffracted light diffracted in the X direction in the seventh region 127 is led to the second light receiving element group 116 and the third light receiving element group 117. Further, the ± first order diffracted light diffracted in the X direction in the eighth region 128 is led to the second light receiving element group 116 and the third light receiving element group 117.

 In addition, the case where the third output light 120 is diffracted by the third polarization hologram element 110 will be described. 7 is a top view showing the configuration of the third polarization hologram element 110 according to the optical pickup device of this embodiment.

As shown in FIG. 7, the third polarization hologram element 110 is similar to the first polarization hologram element 108 in the ninth region 129, the tenth region 130, the eleventh region 131, and the third polarization hologram element 108. It is divided into four regions represented by twelve regions 132. Each divided area is subdivided into rectangular areas, respectively. In the ninth region 129, the ninth rectangular regions 129a and 129b, in the tenth region 130, the tenth rectangular regions 130a and 130b, and in the eleventh region 131, the eleventh rectangular regions 131a, In the twelfth region 132, the twelfth rectangular regions 132a and 132b are alternately arranged. Here, the points where the respective boundary lines of the four regions on the third polarization hologram element 110 intersect substantially overlap each other in plan view with the optical axis of the third semiconductor laser element 114.

The third outgoing light 120 reflected from the surface of the optical information recording medium is diffracted in the X direction shown in FIG. 7 in the ninth region 129 of the third polarization hologram element 110, so that the first-order diffracted light Guided to the first light receiving element group 115 and the third light receiving element group 117. Similarly, ± first-order diffracted light diffracted in the X direction in the tenth region 130 is guided to the first light receiving element group 115 and the third light receiving element group 117. Further, the ± first-order diffracted light diffracted in the X direction in the eleventh region 131 is led to the second light receiving element group 116 and the third light receiving element group 117. Further, the ± first order diffracted light diffracted in the X direction in the twelfth region 132 is guided to the second light receiving element group 116 and the third light receiving element group 117.

As described above, the outgoing light of the semiconductor laser device having the main beam and the sub beam is diffracted by ± 1st order diffracted light in each region formed in the polarization hologram element and is incident on each light receiving element group. Here, the tracking error signal is detected in the main beam and the sub-beam of the semiconductor laser device focused on the first light receiving element group 115 and the # 2 light receiving element group 116. On the other hand, the focus error signal is detected in the main beam of the semiconductor laser device focused to the third light receiving element group 117. When the tracking error signal and the focus error signal are detected, focusing or tracking adjustment is automatically performed to read or write information on the optical information recording medium.

Next, a method of detecting the focus error signal and the tracking error signal will be described in more detail.

First, the diffraction spot of the ± first-order diffracted light incident on each light receiving element group will be described in detail with reference to FIGS. 8 to 11. Fig. 8 is a top view showing the arrangement of light receiving element groups in the optical pickup device of this embodiment.

As shown in FIG. 8, the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 117 disposed on the integrated substrate 112 are respectively in the Y-axis direction. It is divided into a plurality of light receiving areas. The first light receiving element group 115 is divided into four regions represented by the first light receiving element regions 115a, 115b, 115c, and 115d in the Y-axis direction. The second light receiving element group 116 is divided into four regions indicated by the second light receiving element regions 116a, 116b, 116c, and 116d in the Y-axis direction. The third light receiving element group 117 is divided into five regions indicated by the third light receiving element regions 117a, 117b, 117c, 117d, and 117e in the Y-axis direction. The light emitting point L1 of the second semiconductor laser device 113 and the light emitting point L2 of the third semiconductor laser device 114 are disposed between the second light receiving device group 116 and the third light receiving device group 117. Is placed.

Fig. 9 is a top view showing the diffraction spot of the light receiving element group in the first output light 118 according to the optical pickup device of this embodiment. As shown in Fig. 9, the ± first-order diffracted light of the first output light 118 having a main beam and a sub beam is condensed into each of the divided light receiving element regions. The main beam diffraction spots L101c and L104d of the first output light 118 diffracted in the first region 121 (see FIG. 5) are each of the first light receiving element region 115b and the third adjacent to each other. The light is condensed on the boundary lines of the light receiving element regions 117c and 117d. The sub-beam diffraction spots L101a and L101e of the first output light 118 diffracted in the first region 121 (see FIG. 5) are condensed into the first light receiving element regions 115a and 115d, respectively. In addition, the sub-beam diffraction spots L104b and L104f of the first output light 118 diffracted in the first region 121 (see FIG. 5) are separated in both directions along the Y axis from the third light receiving element region 117a, respectively. The light is condensed into the region (hereinafter referred to as region A) and the region (hereinafter referred to as region B) separated from the third light receiving element region 117e in the negative direction of the Y axis. The regions A and B are not formed on the light receiving element region, but are formed on the integrated substrate 112 as a dummy light receiving element or a circuit, for example.

In addition, the main beam diffraction spots L101d and L104c of the first output light 118 diffracted in the second region 122 (see FIG. 5) are formed of the first light receiving element region 115c and the adjacent portions. The light is condensed on the boundary lines of the light receiving element regions 117b and 117c. The sub-beam diffraction spots L101b and L101f of the first output light 118 diffracted in the second region 122 (see FIG. 5) are condensed into the first light receiving element regions 115a and 115d, respectively. Further, the sub-beam diffraction spots L104a and L104e of the first output light 118 diffracted in the second region 122 (see FIG. 5) are condensed into regions A and B, respectively.

The main beam diffraction spots L102d and L103c of the first output light 118 diffracted in the third region 123 (see FIG. 5) are respectively the second light receiving element region 116c and the third light receiving adjacent to each other. The light is collected on the boundary lines of the element regions 117b and 117c. The subbeam diffraction spots L102b and L102f of the first output light 118 diffracted in the third region 123 (see FIG. 5) are condensed into the second light receiving element regions 116a and 116d, respectively. Further, the sub-beam diffraction spots L103a and L103e of the first output light 118 diffracted in the third region 123 (see FIG. 5) are condensed into regions A and B, respectively.

In addition, the main beam diffraction spots L102c and L103d of the first output light 118 diffracted in the fourth region 124 (see FIG. 5) are each of the second light receiving element regions 116b and adjacent to each other. The light is condensed on the boundary lines of the light receiving element regions 117c and 117d. The sub-beam diffraction spots L102a and L102e of the first output light 118 diffracted in the fourth region 124 (see FIG. 5) are condensed into the second light receiving element regions 116a and 116d, respectively. Further, the sub-beam diffraction spots L103b and L103f of the first output light 118 diffracted in the fourth region 124 (see FIG. 5) are condensed into regions A and B, respectively.

Next, the diffraction spot in the case where the ± first-order diffracted light of the second emitted light 119 is collected by the light receiving element group is described. Fig. 10 is a top view showing a light receiving element group diffraction spot of the second output light 119 in the optical pickup device of this embodiment.

As shown in FIG. 10, the ± first-order diffraction light of the second output light 119 having the main beam and the sub-beams is divided into each of the light receiving element regions similar to the ± first-order diffraction light of the first output light 118. Condensed into. The main beam diffraction spots L201c and L204d of the second emission light 119 diffracted in the fifth region 125 (see FIG. 6) are respectively the first light receiving element region 115b and the third light receiving adjacent to each other. The light is condensed on the boundary lines of the element regions 117c and 117d. The sub-beam diffraction spots L201a and L201e of the second emission light 119 diffracted in the fifth region 125 (see FIG. 6) are condensed into the first light receiving element regions 115a and 115d, respectively. Further, the sub-beam diffraction spots L204b and L204f of the second emission light 119 diffracted in the fifth region 125 (see Fig. 6) are condensed into regions A and B, respectively.

In addition, the main beam diffraction spots L201d and L204c of the second emission light 119 diffracted in the sixth region 126 (see FIG. 6) are formed of the first light receiving element region 115c and adjacent to each other. The light is condensed on the boundary lines of the light receiving element regions 117b and 117c. The sub-beam diffraction spots L201b and L201f of the second emission light 119 diffracted in the sixth region 126 (see FIG. 6) are condensed into the first light receiving element regions 115a and 115d, respectively. Further, the sub-beam diffraction spots L204a and L204e of the second emission light 119 diffracted in the sixth region 126 (see FIG. 6) are condensed into regions A and B, respectively.

The main beam diffraction spots L202d and L203c of the second emission light 119 diffracted in the seventh region 127 (see FIG. 6) are respectively the second light receiving element region 116c and the third light receiving adjacent to each other. The light is condensed on the boundary lines of the element regions 117b and 117c. The sub-beam diffraction spots L202b and L202f of the second emission light 119 diffracted in the seventh region 127 (see FIG. 6) are condensed into the second light receiving element regions 116a and 116d, respectively. Further, the sub-beam diffraction spots L203a and L203e of the second output light 119 diffracted in the seventh region 127 (see FIG. 6) are condensed into regions A and B, respectively.

In addition, the main beam diffraction spots L202c and L203d of the second emission light 119 diffracted in the eighth region 128 (see FIG. 6) are each of the second light receiving element regions 116b and adjacent to each other. The light is condensed on the boundary lines of the light receiving element regions 117c and 117d. The sub-beam diffraction spots L202a and L202e of the second output light 119 diffracted in the eighth region 128 (see FIG. 6) are condensed into the second light receiving element regions 116a and 116d, respectively. Further, the sub-beam diffraction spots L203b and L203f of the second emission light 119 diffracted in the eighth region 128 (see FIG. 6) are condensed into regions A and B, respectively.

In addition, the diffraction spot in the case where the ± first-order diffracted light of the third emitted light 120 is collected by the light receiving element group will be described. Fig. 11 is a top view showing a light receiving element group diffraction spot of the third output light 120 according to the optical pickup device of this embodiment.

As shown in FIG. 11, the ± first-order diffraction light of the third output light 120 having the main beam and the sub-beams, as in the ± first-order diffraction light of the first output light 118, is divided into each light receiving element region. Condensed into. The main beam diffraction spots L301c and L304d of the third output light 120 diffracted in the ninth region 129 (see FIG. 7) are each of the first light receiving element region 115b and the third light receiving adjacent to each other. The light is condensed on the boundary lines of the element regions 117c and 117d. The sub-beam diffraction spots L301a and L301e of the third output light 120 diffracted in the ninth region 129 (see FIG. 7) are condensed into the first light receiving element regions 115a and 115d, respectively. Further, the sub beam diffraction spots L304b and L304f of the third output light 120 diffracted in the ninth region 129 (see FIG. 7) are condensed into regions A and B, respectively.

In addition, the main beam diffraction spots L301d and L304c of the third output light 120 diffracted in the tenth region 130 (see FIG. 7) are formed of the first light receiving element region 115c and the adjacent first light receiving element region 115c. The light is condensed on the boundary lines of the light receiving element regions 117b and 117c. The sub-beam diffraction spots L301b and L301f of the third output light 120 diffracted in the tenth region 130 (see FIG. 7) are condensed into the first light receiving element regions 115a and 115d, respectively. In addition, the sub-beam diffraction spots L304a and L304e of the third output light 120 diffracted in the tenth region 130 (see FIG. 7) are condensed into regions A and B, respectively.

The main beam diffraction spots L302d and L303c of the third output light 120 diffracted in the eleventh region 131 (see FIG. 7) are respectively the second light receiving element region 116c and the third light receiving adjacent to each other. The light is condensed on the boundary lines of the element regions 117b and 117c. The sub-beam diffraction spots L302b and L302f of the third output light 120 diffracted in the eleventh region 131 (see FIG. 7) are condensed into the second light receiving element regions 116a and 116d, respectively. The subbeam diffraction spots L303a and L303e of the third output light 120 diffracted in the eleventh region 131 (see FIG. 7) are condensed into regions A and B, respectively.

In addition, the main beam diffraction spots L302c and L303d of the third output light 120 diffracted in the twelfth region 132 (see FIG. 7) are each of the second light receiving element regions 116b and adjacent to each other. The light is condensed on the boundary lines of the light receiving element regions 117c and 117d. The sub-beam diffraction spots L302a and L302e of the third output light 120 diffracted in the twelfth region 132 (see FIG. 7) are condensed into the second light receiving element regions 116a and 116d, respectively. Further, the subbeam diffraction spots L303b and L303f of the third output light 120 diffracted in the twelfth region 132 (see FIG. 7) are condensed into regions A and B, respectively.

As described above, as shown in Figs. 9 to 11, ± first-order diffracted light of the main beam and the sub-beam in each semiconductor laser element is incident on each region of each of the light receiving element groups. In the optical pickup apparatus 101 of this embodiment, for example, a calculation unit formed on an integrated substrate detects a signal output from each light receiving element group, and generates a focus error signal and a tracking error signal based on the detection result. Can be.

Next, a detailed analysis method of the focus error signal and the tracking error signal in the optical pickup apparatus 101 of the present embodiment will be described.

In the optical pickup apparatus 101 of the present embodiment, a known SSD (spot size detection) method is used as a detection method of a focus error signal. In the SSD method, the main beam ± first-order diffracted light of each semiconductor laser element focused on the third light receiving element group 117 is used. Here, the sum of the output signals from the third light receiving element regions 117b and 117d is F1, and the sum of the output signals from the third light receiving element regions 117a, 117c, and 117e is F2. At this time, the focus error signal FE1 by the emitted light of each semiconductor laser element is obtained by the following equation (1).

FE1 = F1-F2... (Eq. 1)

As the detection method of the tracking error signal, a well-known DPD (Phase Difference Detection) method or DPP (Differential Push Pull) method is appropriately selected and used corresponding to each optical information recording medium. In the DPD method, the main beam ± first-order diffracted light of each semiconductor laser device focused on the first light receiving element group 115 and the second light receiving element group 116 is used. On the other hand, in the DPP method, ± first-order diffraction light of the main beam and the sub-beam is used in each of the semiconductor laser devices focused on the first light receiving element group 115 and the second light receiving element group 116.

The output signals from the first light receiving element regions 115b and 115c are referred to as T1 and T2, respectively. The output signals from the second light receiving element regions 116c and 116b are set to T3 and T4, respectively. The sum of the output signals from the first light receiving element regions 115a and 115d is T5, and the sum of the output signals from the second light receiving element regions 116a and 116d is T6. At this time, the tracking error signal TE (DPD) using the DPD method by the emission light of each semiconductor laser element is obtained by the following formula (2).

TE (DPD) = (Phase Comparison of T1 and T4) + (Phase Comparison of T2 and T3)... (Eq. 2)

The tracking error signal TE (DPP) using the DPP method by the emitted light of each semiconductor laser element is obtained by the following equation.

TE (DPP) = (T1 + T2)-(T3 + T4) -k (T5-T6)... (Eq. 3)

Here, in said Formula 3, k is arbitrary value.

By using each of the detection methods described above, the optical pickup device 101 of the present embodiment can analyze the focus error signal and the tracking error signal, and can perform the focus adjustment and the tracking adjustment.

Effect of optical pickup

The optical pickup apparatus 101 of this embodiment includes three semiconductor laser elements in accordance with Blu-ray Disc, DVD, and CD standards, and the two semiconductor laser elements and the light receiving element group include one light source / detection unit. It consists of a structure arrange | positioned at 107. As a result, the number of parts can be reduced as compared with the conventional optical pickup apparatus having the light source / detection unit for each wavelength. In addition, since the collimating lens 103, the quarter wave plate 106, the objective lens (not shown), the beam separator 102, and the respective light receiving element groups are shared, the number of parts can be further reduced. As a result, it is possible to meet the standards of three different types of optical information recording media, and it is possible to realize a miniaturized optical pickup apparatus.

In the optical pickup device 101 of the present embodiment, the light source / detecting unit 107 has a second diffraction grating 111 and an integrated substrate 112, and is easy to assemble.

In addition, in the optical pickup device 101 of the present embodiment, the first semiconductor laser element 104 is disposed outside the light source / detecting unit 107, so that the first output light 118 is not transmitted via the polarization hologram element. The information recording medium can be focused. As a result, the energy loss of the laser light due to passing through the polarizing hologram element can be suppressed, so that the optical pick-up device is realized, and the optical pickup device capable of recording at high speed is realized.

In the optical pickup device 101 of the present embodiment, it is preferable that the first semiconductor laser element 104 that emits the shortest wavelength laser light is disposed outside the light source / detecting unit 107. In general, the laser beam having a shorter wavelength increases in energy loss when passing through the polarization hologram element. Therefore, by disposing the first semiconductor laser element 104 on the outside, it is possible to more effectively use the emitted light of the semiconductor laser element.

In addition, in the optical pickup device 101 of the present invention, the main beam of the first exiting light 118 and the main beam of the second exiting light 119 on the collimating lens 103 and the optical axis of the collimating lens 103. It is desirable to match. As a result, the light emitted from each of the first semiconductor laser device 104 and the second semiconductor laser device 113 is incident on the objective lens at an optimal position and angle, thereby improving the quality of the beam spot shape on the optical information recording medium. This makes it possible to accurately record and play back Blu-ray Discs and DVDs. As a result, a high-performance optical pickup device corresponding to the standard of each optical information recording medium can be realized.

In the optical pickup device 101 of this embodiment, an unpolarized light hologram element may be used instead of the third polarization hologram element. Thus, even when the optical information recording medium corresponding to the wavelength of the third output light 120 is a coarse optical information recording medium, the writing operation can be stably performed.

Here, in the optical pickup device 101 of the present embodiment, the first semiconductor laser device 104 is arranged such that the main beam of the first output light 118 is orthogonal to the optical axis of the collimating lens 103. It is not limited.

In addition, in the optical pickup device 101 of the present embodiment, the configuration in which the quarter wave plate 106 is disposed between the beam separator 102 and the collimating lens 103 has been described, but the present invention is not limited thereto. A quarter wave 106 is placed on the optical path of the first outgoing light 118, the second outgoing light 119, and the third outgoing light 120 between the collimating lens 103 and the objective lens. The arrangement may be used. In such a configuration, the same effects as described above can be obtained.

The objective lens included in the optical pickup apparatus 101 of the present invention may be composed of one lens or a combination lens composed of a plurality of lenses. Moreover, you may comprise the lens for a 1st semiconductor laser, the lens for a 2nd semiconductor laser, and a 3rd semiconductor laser, respectively. In any case, the same effects as described above can be obtained.

In the optical pickup apparatus 101 of this embodiment, although a Blu-ray Disc is mentioned as one of the optical information recording media, the same effects as described above can be obtained even when HD DVD is used without being limited thereto. It is also possible to use the optical pickup apparatus of the present invention for all optical information recording media having a standard corresponding to a semiconductor laser of 405 nm band.

Second Embodiment

Next, the configuration of the optical pickup apparatus according to the second embodiment of the present invention and the operation of the optical pickup apparatus will be described with reference to the drawings. In the optical pickup apparatus of this embodiment, the collimating lens is arranged at a position different from that of the optical pickup apparatus of the first embodiment described above.

-Composition of optical pickup device

12 is a cross-sectional view showing the construction of an optical pickup apparatus according to a second embodiment of the present invention. As shown in Fig. 12, the optical pickup apparatus of this embodiment is provided with three semiconductor laser elements so as to correspond to three types of optical information recording media. The first semiconductor laser device 104 emits 405 nm band laser light (first output light 118, see FIG. 13) in accordance with the Blu-ray Disc standard. The second semiconductor laser element 113 emits a 650 nm laser beam (second emission light 119, see FIG. 14) in accordance with the DVD standard, and the third semiconductor laser element 114 conforms to the CD standard. One 780 nm laser light (third output light 120, see Fig. 15) is emitted.

The optical pickup device 201 of this embodiment includes a first semiconductor laser device 104, a first diffraction grating 105, a beam splitter 102, a quarter wave plate 106, and a collimating lens 103. , A first polarization hologram element 108 and a second polarization hologram element 109 sequentially arranged from the light splitter 102 side between the light source / detection unit 107, the light source / detection unit 107, and the beam separator 102. And a third polarization hologram element 110. The first diffraction grating 105 is disposed between the first semiconductor laser device 104 and the beam splitter 102. Further, the quarter wave plate 106 is disposed between the beam splitter 102 and the collimating lens 103.

The light source / detecting unit 107 includes an integrated substrate 112, a second semiconductor laser device 113, a third semiconductor laser device 114, a first light receiving device group 115, and a second light receiving device group 116. , A third light receiving element group 117, and a second diffraction grating 111. Here, the second diffraction grating 111 is formed on the lower surface of the transparent member 511 made of a glass plate or the like so as to be positioned above the second semiconductor laser device 113 and the third semiconductor laser device 114.

In the optical pickup device 201 of this embodiment, the positional relationship between the first semiconductor laser element 104 and the light source / detecting unit 107 and the collimating lens 103 is different from that of the optical pickup device of the first embodiment. That is, in the optical pickup device 201 of the present embodiment, the collimating lens 103 has the optical axis of the collimating lens 103 as the main beam of the second output light 119 and the main of the third output light 120. It is arranged to be orthogonal to the beam. The second output light 119 and the third output light 120 enter the beam splitter 102 via the second diffraction grating 111. In the beam splitter 102, the second output light 119 and the third output light 120 are reflected, and the reflected light is guided to the collimating lens 103.

Meanwhile, the first output light 118 passes through the beam splitter 102. Further, the reflected light from the optical information recording medium is transmitted to the first polarizing hologram element 108, the second polarizing hologram element 109, and the third polarizing hologram element 110 through the beam separator 102.

Here, the first polarization hologram element 108 is designed to diffract the first output light 118 and transmit the second output light 119 and the third output light 120. Similarly, the second polarization hologram element 109 diffracts only the second output light 119. In addition, the third polarization hollog RAM device 110 diffracts only the third output light 120.

Operation of optical pickup device

The operation of the optical pickup device 201 according to the present embodiment will be described with reference to FIGS. 13 to 15. In the optical pickup apparatus 201 of this embodiment, like the first embodiment, after the standard conforming to the optical information recording medium is determined, the laser light is irradiated to the optical information recording medium using a semiconductor laser element corresponding to the conforming standard. do.

13 is a cross-sectional view showing the optical path of the first output light 118 in the optical pickup device 201 of this embodiment.

As shown in FIG. 13, the first output light 118 is diffracted by the first diffraction grating 105 into a main beam and a sub beam. The diffracted first output light 118 passes through the beam splitter 102 and passes through the quarter wave plate 106 and then parallelized by the collimating lens 103. Thereafter, the first output light 118 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The first output light 118 reflected from the recording surface is reflected by the beam splitter 102 and enters the first polarization hologram element 108. The first output light 118 is diffracted by the first polarization hologram element 108 into ± 1st diffraction light, and then passes through the second polarization hologram element 109 and the third polarization hologram element 110. Thereafter, the first output light 118 enters the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 117.

14 is a cross-sectional view showing the optical path of the second output light 119 in the optical pickup device 201 of this embodiment.

As shown in FIG. 14, the second output light 119 is diffracted from the second diffraction grating 111 into a main beam and a sub beam. The diffracted second output light 119 is reflected by the beam splitter 102, then passes through the quarter wave plate 106 and is parallelized by the collimating lens 103. Thereafter, the second output light 119 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The second outgoing light 119 reflected from the recording surface is reflected by the beam splitter 102 via the same optical path as the exit path, then passes through the first polarization hologram element 108 and the second polarization hologram element 109. Incident The second output light 119 is diffracted by the second polarization hologram element 109 into ± first order diffracted light, and then passes through the third polarization hologram element 110. Thereafter, the second emission light 119 enters the first light receiving element group 115, the second light receiving element group 116, and the third light receiving element group 117.

15 is a cross-sectional view showing the optical path of the third output light 120 in the optical pickup device 201 of this embodiment.

As shown in FIG. 15, the third output light 120 is diffracted in the second diffraction grating 111 into the main beam and the sub beam, similarly to the second output light 119. The diffracted third output light 120 is reflected vertically at the beam splitter 102 and then passes through the quarter wave plate 106 and is parallelized by the collimating lens 103. Thereafter, the third output light 120 is focused on the recording surface of the optical information recording medium by an objective lens (not shown). The third output light 120 reflected from the recording surface is reflected by the beam splitter 102 through the same optical path as the exit path, and then passes through the first polarization hologram element 108 and the second polarization hologram element 109. And incident on the third polarization hologram element 110. In addition, the third output light 120 is diffracted by the first polarization hologram element 110 into ± 1st order diffracted light, and then the first light receiving element group 115, the second light receiving element group 116, And incident to the third light receiving element group 117.

As described above, the outgoing light of each semiconductor laser element is reflected by the recording surface of the optical information recording medium, and then diffracted by ± 1st order diffracted light in the polarization hologram element corresponding to each wavelength, and enters into each light receiving element group. In each light receiving element group, incident light is processed, converted into a tracking error signal, a focus error signal, and information data, so that information can be recorded or reproduced on the optical information recording medium.

Effect of optical pickup

The optical pickup device 201 of this embodiment includes three semiconductor laser devices conforming to the standards of Blu-ray Disc, DVD, and CD as in the first embodiment, and the two semiconductor laser devices and the light receiving device group It is comprised in one light source / detection unit 107. The optical pickup device 201 of this embodiment shares the collimating lens 103, the quarter wave plate 106, the objective lens (not shown), the beam separator 102, and each of the light receiving element groups. . The light source / detection unit 107 includes a second diffraction grating 111 and an integrated substrate 112. This makes it possible to meet three types of optical information recording medium standards, reduce the number of parts, and realize an optical pickup device that is compact and easy to assemble.

In the optical pickup device 201 of this embodiment, it is preferable that the first semiconductor laser element 104 for emitting the shortest wavelength laser light is disposed outside the light source / detecting unit 107. As a result, the energy loss when the laser beam passes through the polarization hologram element can be suppressed, so that the light emitted from the semiconductor laser element can be used more effectively.

In the optical pickup device 201 of this embodiment, the main beam of the first output light 118 and the main beam of the second output light 119 on the collimating lens 103 are the optical axes of the collimating lens 103. Preferably coincides with As a result, the light emitted from each of the first semiconductor laser device 104 and the second semiconductor laser device 113 is incident at an optimal position and angle with respect to the objective lens, thereby improving the quality of the beam spot shape on the optical information recording medium. Therefore, recording and playback of Blu-ray Discs and DVDs can be performed with high accuracy. As a result, a high-performance optical pickup device corresponding to the standard of each optical information recording medium can be realized.

In the optical pickup device 201 of the present embodiment, a polarized hologram element may be used instead of the third polarized hologram element. Thereby, even when the optical information recording medium corresponding to the wavelength of the third output light 120 is a coarse optical information recording medium, the writing operation can be stably performed.

In addition, in the optical pickup device 201 of the present embodiment, the second semiconductor laser element is arranged such that the main beam of the second output light 119 and the main beam of the third output light 120 are perpendicular to the optical axis of the collimating lens 103. Although the example in which the 113 and the third semiconductor laser elements 114 are disposed has been described, the present invention is not limited thereto.

Third Embodiment

The configuration of the optical pickup apparatus according to the third embodiment of the present invention and the operation of the optical pickup apparatus will be described with reference to the drawings. The optical pickup apparatus of this embodiment includes a semiconductor laser element having a structure different from that of the optical pickup apparatus according to the first embodiment described above.

16 is a cross-sectional view showing the construction of an optical pickup apparatus according to a third embodiment of the present invention. As shown in Fig. 16, the optical pickup device 301 of this embodiment is composed of a first semiconductor laser element 104 and a monolithic two-wavelength semiconductor laser element in order to correspond to three types of optical information recording media. A fourth semiconductor laser device 313 is provided.

The optical pickup device 301 of this embodiment includes a first semiconductor laser element 104, a first diffraction grating 105, a beam splitter 102, a quarter wave plate 106, and a collimating lens 103. ), The first polarization hologram element 108 and the second polarization hologram element disposed sequentially from the light splitter 102 side between the light source / detection unit 107, the light source / detection unit 107, and the beam separator 102. 109, and a third polarization hologram element 110.

The light source / detecting unit 107 includes an integrated substrate 112, a fourth semiconductor laser element 313, a first light receiving element group 115, a second light receiving element group 116, and a third light receiving element group 117. ) And a second diffraction grating 111. The second diffraction grating 111 is formed on the lower surface of the transparent member 511 made of a glass plate or the like so as to be positioned above the fourth semiconductor laser element 313.

The optical pickup apparatus 301 of this embodiment having the above configuration can perform information recording or reproduction of each optical information recording medium by the same operation as that of the optical pickup apparatus 101 of the first embodiment described above.

The optical pickup device 301 of the present embodiment is characterized in that the fourth semiconductor laser element 313 is composed of a monolithic two-wavelength semiconductor laser element that emits 650 nm laser light and 780 nm laser light. The laser element 313 and the light receiving element group are configured in one light source / detection unit 107. This makes it possible to support two optical information recording medium standards with one semiconductor laser element, so that the number of parts can be reduced. In addition, the optical pickup device 301 of this embodiment shares the collimating lens 103, the quarter wave plate 106, the objective lens (not shown), the beam separator 102, and each of the light receiving element groups. . The light source / detection unit 107 also includes a second diffraction grating 111 and an integrated substrate 112. As a result, an optical pickup apparatus that can cope with the standards of three types of optical information recording media and can be miniaturized and easily assembled can be realized.

In addition, by using the monolithic two-wavelength semiconductor laser element, the accuracy of the interval between the semiconductor laser elements arranged adjacent to the substrate, the so-called light beam emission interval, can be improved. In general, when a monolithic two-wavelength semiconductor laser element is not used, that is, when two kinds of semiconductor laser elements are used, respectively, the precision of the light beam emission interval depends on the assembly precision. At this time, when two kinds of semiconductor laser elements are separately mounted on the integrated substrate, the light beam emission interval includes a large error of about 10 mu m. On the other hand, in the case of using a monolithic two-wavelength semiconductor laser element, the precision of the light beam emission interval depends on the diffusion accuracy. Here, the diffusion precision refers to the precision of the diffusion mask used when the semiconductor laser device is formed on the substrate. In this case, by forming a monolithic two-wavelength semiconductor laser element on the substrate using a diffusion mask, the error of the light beam emission interval can be suppressed to about 1 μm or less. Therefore, the precision of the light beam emission interval is improved when the monolithic two-wavelength semiconductor laser element is used. As a result, since the laser beam of the fourth semiconductor laser element 313 composed of the monolithic two-wavelength semiconductor laser element is emitted with high precision, recording or reproduction of an optical information recording medium having a standard corresponding to the wavelength of the laser beam is performed. Can improve the precision.

In the optical pickup device 301 of the present embodiment, a non-polarization hologram element may be used instead of the third polarization hologram element. This makes it possible to stably perform the writing operation even when the optical information recording medium corresponding to the wavelength of the third output light 120 is a coarse optical information recording medium.

Here, also in the optical pickup apparatus 301 of this embodiment, the same effects as those in the optical pickup apparatus of the first embodiment described above can be obtained.

Further, in the optical pickup device 301 of this embodiment, an example in which the second semiconductor laser device and the third semiconductor laser device in the optical pickup device of the first embodiment described above are replaced with a monolithic two-wavelength semiconductor laser device has been described. It is not limited to this, For example, you may use a monolithic 2 wavelength semiconductor laser element for the optical pickup apparatus 201 of 2nd Example mentioned above.

The two types of laser light emitted by the monolithic two-wavelength semiconductor laser element in the optical pickup device 301 of the present embodiment are 650 nm laser light and 780 nm laser light, but the present invention is not limited thereto. Laser beams of nm nm and laser beams of 650 nm, laser beams of 405 nm and laser beams of 780 nm may be used.

[Example 4]

The configuration of the optical pickup apparatus according to the fourth embodiment of the present invention and the operation of the optical pickup apparatus will be described with reference to the drawings. The optical pickup apparatus of this embodiment includes a polarization hologram element having a structure different from that of the optical pickup apparatus according to the first embodiment described above.

Fig. 17 is a sectional view showing the construction of an optical pickup device 401 according to the fourth embodiment of the present invention. As shown in Fig. 17, the optical pickup device 401 of this embodiment is provided with three semiconductor laser elements so as to correspond to three types of optical information recording media.

The optical pickup device 401 of the present embodiment includes a first semiconductor laser element 104, a beam separator 102, a quarter wave plate 106, a collimating lens 103, a light source / detecting unit 107. ), A fourth polarization hologram element 418 configured between the light source / detection unit 107 and the beam separator 102.

The fourth polarization hologram element 418 is composed of a first polarization hologram element 108, a second polarization hologram element 109, and a third polarization hologram element 110 arranged sequentially from the beam splitter 102 side. . Here, the polarizing hologram elements which are in contact with each other are bonded to each other with an adhesive or the like.

The light source / detection unit 107 includes an integrated substrate 112, a second semiconductor laser device 113, a third semiconductor laser device 114, a first light receiving device group 115, and a second light receiving device group 116. ), A third light receiving element group 117, and a second diffraction grating 111. The second diffraction grating 111 is formed above the second semiconductor laser device 113 and the third semiconductor laser device 114 on the lower surface of the transparent member 511 made of a glass plate or the like.

The optical pickup apparatus 401 of the present embodiment having the above configuration can record or reproduce information on each optical information recording medium by the same operation as that of the optical pickup apparatus of the first embodiment described above.

The optical pickup device 401 of the present embodiment is characterized by an integrated fourth polarization hologram element composed of a first polarization hologram element 108, a second polarization hologram element 109, and a third polarization hologram element 110. 418). By using the integrated polarization hologram element, the assembling accuracy of the polarization hologram element can be improved as compared with the case where each polarization hologram element is individually configured. As a result, it is possible to realize an optical pickup device that is compact and easy to assemble.

In the optical pickup device 401 of this embodiment, a polarized hologram element may be used instead of the third polarized hologram element. This makes it possible to stably perform the writing operation even when the optical information recording medium corresponding to the wavelength of the third output light 120 is a coarse optical information recording medium.

Here, also in the optical pickup device 401 of this embodiment, the same effects as in the optical pickup device of the first embodiment can be obtained.

In the optical pickup device 401 of this embodiment, an example in which each polarization hologram element in the optical pickup device of the first embodiment is replaced with an integral fourth polarization hologram element 418 has been described, but is not limited thereto. For example, an integrated polarization hologram element may be used for the optical pickup device of the second embodiment and the optical pickup device of the third embodiment described above.

[Example 5]

The structure of the optical pickup apparatus according to the fifth embodiment of the present invention and the operation of the optical pickup apparatus will be described with reference to the drawings. The optical pickup apparatus of this embodiment has a light source / detection unit and a polarization hologram element having a different configuration from the optical pickup apparatus according to the first embodiment described above.

18 is a cross-sectional view showing the configuration of an optical pickup apparatus according to a fifth embodiment of the present invention. As shown in Fig. 18, the optical pickup device 501 of this embodiment is provided with three semiconductor laser elements so as to correspond to three types of optical information recording media.

The optical pickup device 501 of this embodiment includes a first semiconductor laser element 104, a beam separator 102, a quarter wave plate 106, a collimating lens 103, a light source / detecting unit 107. ), A diffraction grating integrated polarization hologram element 518 formed on the light source / detecting unit 107 is provided.

The light source / detecting unit 107 includes an integrated substrate 112, a second semiconductor laser element 113, a third semiconductor laser element 114, a first light receiving element group 115, and a second light receiving element group 116. ) And a third light receiving element group 117.

The diffraction grating integrated polarization hologram element 518 includes a first polarization hologram element 108, a second polarization hologram element 109, a third polarization hologram element 110, which are arranged in order from the beam splitter 102 side, and It consists of a second diffraction grating 111. Here, the second diffraction grating 111 is formed on the lower surface of the transparent member 511 made of a glass plate or the like so as to be positioned above the second semiconductor laser device 113 and the third semiconductor laser device 114. Here, the polarization hologram elements in contact with each other, the third polarization hologram element 110 and the transparent member 511, and the transparent member 511 and the light source / detecting unit 107 are each bonded by an adhesive or the like, for example.

The optical pickup apparatus 501 of the present embodiment having the above configuration can record or reproduce information on each optical information recording medium by the same operation as that of the optical pickup apparatus of the first embodiment described above.

The optical pickup device 501 of this embodiment has a diffraction grating integrated polarization hologram element 518 composed of a second diffraction grating and each polarization hologram element, and also includes a diffraction grating integrated polarization hologram element 518 and a light source. The detection unit 107 is integrated. Thereby, assembling accuracy of each polarization hologram element, the second diffraction grating, and the light source / detecting unit can be improved as compared with the case where each member is individually configured. As a result, it is possible to realize an optical pickup device that is compact and easy to assemble.

In the optical pickup device 501 of this embodiment, the thickness of the transparent member 511 provided in the diffraction grating integrated polarization hologram element 518 is larger than that of the optical pickup device of the first embodiment. As a result, the distance between each polarization hologram element and the second diffraction grating 111 can be sufficiently secured, so that the ± 1st order diffracted light from each polarization hologram element does not pass through the second diffraction grating 111. Can be collected, the optical pickup device 501 can obtain a stable signal.

In the optical pickup device 501 of this embodiment, a polarized hologram element may be used instead of the third polarized hologram element. This makes it possible to stably perform the writing operation even when the optical information recording medium corresponding to the wavelength of the third output light 120 is a coarse optical information recording medium.

Here, also in the optical pickup apparatus 501 of this embodiment, the same effects as those in the optical pickup apparatus of the first embodiment described above can be obtained.

According to the optical pickup apparatus of the present invention, three different semiconductor laser elements are used, and two semiconductor laser elements are configured in the same light source / detection unit, and each component is shared regardless of the type of laser light. It is possible to record and reproduce information on three types of optical information recording media, to reduce the number of parts, to miniaturize, and to realize an optical pickup device that is easy to assemble.

Further, the present invention is useful for an optical pickup apparatus that records or plays back information, for example, on a Blu-ray Disc, a DVD, a CD or the like.

Claims (18)

A first semiconductor laser device for emitting a first light beam; A second semiconductor laser device that emits a second light beam; A third semiconductor laser device for emitting a third light beam, A collimating lens for paralleling the first light beam, the second light beam, and the third light beam; A beam splitter configured to reflect or transmit the first light beam, the second light beam, and the third light beam to focus the collimating lens; A first hologram element which is reflected at the recording surface of the optical information recording medium and diffracts the first light beam having passed through the beam separator into ± 1st order diffracted light; A second hologram element that reflects the second light beam reflected by the recording surface of the optical information recording medium and passed through the beam splitter into ± 1st order diffracted light; A third hologram element for diffracting the third light beam reflected by the recording surface of the optical information recording medium and passing through the beam splitter with ± 1st order diffracted light;    And a plurality of light receiving element groups for receiving the ± first order diffracted light diffracted by the first hologram element, the second hologram element, and the third hologram element, And the second semiconductor laser element, the third semiconductor laser element, and the plurality of light receiving element groups are configured in the same light source / detection unit.        The method according to claim 1,        And a first diffraction grating disposed on an optical path of the first light beam from the first semiconductor laser device to the beam splitter, the first diffraction grating diffracting the first light beam into a main beam and a sub beam. Pickup device.         The method according to claim 1,        The second light beam from the second semiconductor laser device to the beam splitter, and the optical path of the third light beam from the third semiconductor laser device to the beam splitter, the second light beam and the third light beam. And a second diffraction grating for diffracting the beam into a main beam and a sub beam.         The method according to claim 3,        And said second diffraction grating is disposed above said light source / detection unit above said second semiconductor laser element and said third semiconductor laser element.         The method according to claim 3,        And said first hologram element, said second hologram element, and said third hologram element are disposed between said beam splitter and said second diffraction grating.         The method according to claim 5,        And the first hologram element, the second hologram element, and the third hologram element are integrally formed.         The method according to claim 6,        And said first hologram element, said second hologram element, said third hologram element, and said second diffraction grating are integrally formed with said light source / detection unit.         The method according to claim 1,        The wavelength of the first light beam is A, the wavelength of the second light beam is B, and the wavelength of the third light beam is C, wherein A < B < C.         The method according to claim 8,        And the first light beam is a light beam of 405 nm band, the second light beam is a light beam of 650 nm band, and the third light beam is a light beam of 780 nm band.         The method according to claim 1,        And the main beam of the first light beam and the main beam of the second light beam substantially coincide with the optical axes of the collimating lens on the collimating lens.         The method according to claim 1,        And said second semiconductor laser element and said third semiconductor laser element are integrally formed as a monolithic two-wavelength semiconductor laser element.         The method according to claim 1,        The first hologram element transmits the second light beam and the third light beam, the second hologram element transmits the first light beam and the third light beam, and the third hologram element transmits the first light beam and the third light beam. An optical pickup apparatus, characterized by transmitting a second light beam.         The method according to claim 1,        And the first hologram element, the second hologram element, and the third hologram element are all polarized hologram elements.         The method according to claim 1,        And both the first hologram element and the second hologram element are polarization hologram elements, and the third hologram element is a non-polarization hologram element.         The method according to claim 1,        And a quarter wave plate is further provided between the beam splitter and the collimating lens.         The method according to claim 1,        An objective lens for condensing the first light beam, the second light beam and the third light beam paralleled by the collimating lens to the optical information recording medium;        And a quarter wave plate disposed on the optical path of the first light beam, the second light beam, and the third light beam between the collimating lens and the objective lens.         The method according to claim 1,         And the main beam of the first light beam substantially coincides with the optical axis of the collimating lens.         The method according to any one of claims 1 to 17, And an operation unit for detecting an electrical signal output from the plurality of light receiving element groups and generating a focus error signal or a tracking error signal based on the detection result.

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